Question

7. A 68.5-kg astronaut is doing a repair in space on the orbiting space

station. She throws a 2.25-kg tool away from her at 3.20 m/s relative to

the space station. With what speed and in what direction will she begin

to move?

Answer 1

Apply momentum conservation to get the answer:

$$0=m_Av_a-m_tv_t,\\\space\\ v_a=\frac{m_tv_t}{m_a}=\frac{2.25·3.2}{68.5}=0.105\text{ m/s}.$$